Stop guessing when to reorder. Get the exact inventory level that keeps you in stock without drowning in dead capital.
Units sold per day on average
Days from order placed to stock arrival
Extra days of buffer stock (default: 7)
Units currently in stock (for days remaining estimate)
Stockouts are silent profit killers. You do not just lose the sale — you lose the ad spend that drove the click, the SEO ranking that took months to build, and the customer who will now buy from your competitor instead.
A reorder point is the exact inventory level that tells you: place your next purchase order now. Not a vague "we're getting low" feeling — an actual number. When your stock on hand hits that number, you order. By the time the shipment arrives, you still have enough inventory to cover every customer who walks through your digital door.
Order too late and you run out. Order too early and you tie up cash that should be working elsewhere. For ecommerce brands selling on Shopify or through DTC channels, the cost of getting this wrong is steep in both directions. A well-calculated reorder point removes the guesswork entirely.
The formula is simple — two components added together. But getting the inputs right is what separates brands that always ship on time from brands that scramble with "out of stock" notices.
Reorder Point = (Daily Sales × Lead Time) + (Daily Sales × Safety Stock Days)
Here is how it works in practice. Say you sell 10 units per day and your supplier takes 14 days to deliver. That means you will sell 140 units during the waiting period — that is your lead time demand. Now add your safety buffer. With 7 safety days at 10 units per day, that is another 70 units.
Your reorder point: 210 units. When your inventory hits 210, you place the order. By the time the shipment arrives 14 days later, you have sold through roughly 140 units, and your 70-unit safety buffer is still intact. That is the beauty of it — your customers never notice a thing.
If your suppliers are unreliable or your demand is seasonal, bump up your safety days. If your supply chain is tight and predictable, you can run leaner.
Your forecast will be wrong. That is not a criticism — it is a fact of ecommerce. A viral TikTok post can double your daily orders overnight. A supplier can miss a delivery window by a week. Shipping disruptions can add days to your lead time with zero warning. Safety stock is your insurance against all of it, the buffer that absorbs the shocks so your customers never see an "out of stock" message.
But that is only half the picture — how much safety stock you need depends on your specific risk profile:
Most DTC brands land on 7 to 14 days of safety stock as the sweet spot between protection and capital efficiency. Start with 7 days, track how close you come to running out, and adjust. A few extra days of inventory costs pennies compared to a stockout — which burns your ad spend, damages your SEO rankings, and hands your customer lifetime value to a competitor.
It is the exact inventory number that tells you to place your next purchase order. When your stock on hand hits this level, you order — and your new shipment arrives before you run out. The number accounts for how many units you will sell while waiting for delivery, plus a safety buffer for surprises. No guesswork, no spreadsheet panic.
Multiply your average daily unit sales by the number of buffer days you want. Selling 10 units per day and want a 7-day cushion? Your safety stock is 70 units. The right number of buffer days depends on three things: how much your demand fluctuates, how reliable your supplier is, and how painful a stockout would be for your business. Most DTC brands start at 7 days and adjust from there.
You run out of stock. And the damage goes beyond the lost sale. Every dollar you spent driving traffic to that product page is wasted — your ads, your SEO, your email campaigns all funneled customers to a dead end. Your search rankings drop because Google sees zero engagement on out-of-stock pages. And the customer who was ready to buy? They just discovered your competitor. The savings from carrying less inventory rarely survive a single stockout.
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